The Application Of CT Dual Energy Imaging In The Gastric Cancer

Part One Evaluate the value of dual energy imaging in early gastric cancerObjective:To study the application dual-source CT spectral curve and the iodine concentration in the diagnosis early gastric cancer.Methods:Seventeen patients (8men,9women, age range32-69, mean age45.6) with gastric cancer which was confirmed by endoscopy or operation pathology and thirty patients (13men,17women, age range28-62, mean age54.3) underwent dual-energy scanning with SOMATOM Definition Flash CT.The iodine concentration of the lesion in arterial phase and venous phase was measured respectively,and small curvature side for the normal was also measured,including the iodine concentration aorta of same level.Then the NIC was obtained through counting.Compare the difference between the normal and early gastric wall,analysis the feature of the spectrum curve. Results:Among17cases,7cases were cancer in-situ,10cases were submucosal carcinoma.The NIC of early gastric cancer in arterial phase and venous phase were0.363±0.079、0.782±0.242;30normal gastric wall were0.164±0.064、0.422±0.113.There are statistical significance. Although both of the normal and early gastric cancer spectrum curve were descent tendency,there are difference between them especially during the40kev to70kev.The gastric cancer spectrum curve were above the normal wall,and the early gastric cancer were sheer.During the80kev-140kev the difference was trail off.In the ROC curve,when the threshold was5.573in arterial phase,the sensitivity was82.7%,the specificity was84.8%; when the threshold was6.67in venous phase,the sensitivity was64.7%,the specificity was97%.Conclusion:The normalized iodine concentration and the feature of the spectrum curve were helpful to identify the early gastric cancer and normal through the dual-energy model scan. Part Two The preliminary research of dual energy CT in advanced gastric cancerObjective:Compare the difference of the NIC between poor and well differentiation in arterial and venous phase, analysis the NIC of the metastasis lymph node and non-metastasis lymph node. To evaluate the value of virtual non-contrast images (VNC) reconstructed from contrast-enhanced, dual-energy scans in advanced gastric cancer, compared to single-energy, true non-contrast images (TNC). Methods:Seventy-seven patients (47men,30women, age range23-81, mean age56.74) with gastric cancer which was confirmed by endoscopy or operation pathology underwent dual-energy scanning with SOMATOM Definition Flash CT. Measuring gastric1lesions iodine concentration multiple times in arterial and venous phase esions respectively and the aorta of the same layer.The metastasis lymph nodes and non-metastasis lymph nodes that were confirmed by pathology were also analysis and surveyed.77patients with advanced gastric cancer accepted a dual-phase CT on a second-generation Definition Flash-CT scanner, containing an unenhanced single-energy scan at120kV (group A)and virtual non-contrast images (VNC) reconstructed from contrast enhanced DE-CT (100kV/SN140kV) in an arterial phase(group B) and venous phase(group C) respectively, were retrospectively analyzed. The mean attenuation of the lesions and standard deviation (SD) of which were measured; signal to noise ratio (SNR) were calculated within the corresponding VNC and TNC images. image quality was recorded. One-way ANOVA and Pearson correlation were used for statistical analysis.Results:There are41well differentiation gastric carcinoma (34men,7women, mean age60.45),36poor differentiation gastric carcinoma(13men,23women, mean age39.7).In arterial phase,the NICOf poor differentiation the first layer is0.360±0.084, the second layer is0.104±0.032,while the well differentiation is the first layer is0.411±0.092,the second layer is0.253±0.085.In venous phase, the NICOf poor differentiation the first layer is0.895±0.333, the second layer is0.283±0.092, while the well differentiation the first layer is0.911±0.243,the second layer is0.701±0.177. There are Statistical differences about the second laye’s NIC.The metastasis lymph nodes NIC is0.557±0.093and0.465±0.009, while the non-lymph nodes NIC is0.105±0.064and0.215±0.091.No significant differences in the mean attenuation of the lesions were found among the three groups. However, SD of lesions in group B(5.09±1.81) and C(5.09±1.88) were significantly lower than that in group A(9.12±2.46)(P=0.000), SNR of lesions in group B(8.88±4.91) and C (7.19±3.06)were significantly higher than that in group A(4.43±1.37)(P=0.000),with no differences between the group Band C (P>0.05). Image quality of two VNC sets(4.86±0.16score,4.88±0.12score) were both decreased compared with TNC(4.93±0.06score)(P=0.052)Conclusion:The normalized iodine concentration was helpful to identify the degree of differentiation of gastric cancer and the nature of lymph nodes.To advanced gastric cancer,the VNC images of artery and venous phase had no difference,and had higher SNR than CNC.There was no difference between CNC and VNC.Therefore the VNC can be spread to decrease the radiation dose.